Sensitive relay



Oct. 15 H T- us L SENSITIVE RELAY Filed Feb. 1, 1956 lnvemors:

Harold 1'. Fcus Curl L.Pike

.4 z. 44 Their AHorney United States Patent SENSITIVE RELAY Harold T. Fans and Carl L. Pike, Lynn, Mass., assignors to General Electric Company, a corporation of New York The present invention relates to improved movingarmature electromechanical devices and, in one aspect, to sensitive polarized relays of simple and low-cost construction having rapid response and high sensitivity charactenstics.

In electromagnetic devices having movable magnetized armatures, the sensitivity and speed of armature response to lnfluences of electromagnetic fields is of course related to the inertias of such armatures. Additionally, the electromagnetic field strengths and distributions about such armatures are highly critical. It thus commonly results that devices of this character must be provided with relatively heavy electrical windings which will develop substantial electromagnetic fluxes, cores of large cross-section which will concentrate such fluxes in regions where maximum interactions with the armatures can occur, and precisely machined pole pieces which will accurately distribute fluxes and magnetic poles. Furthermore, the configurations of armatures may be complicated and the positioning of such armatures in relation to associated electromagnet core structures must often be precise. Satisfaction of these requirements leads to rather bulky and weighty devices which may also be costly and difiicult to assemble and maintain in adjustment. It is in avoidance of such difficulties and disadvantages that the present teachings are particularly advantageous.

Thus, an object of this invention is to provide improved movable-armature electromagnetic devices wherein rapid response and high sensitivity are achieved with simple and readily-fabricated structure.

A further object is to provide a polarized relay of low cost, size, and weight which possesses great sensitivity and which resists effects of shock and vibration.

By way of a summary account of our invention in one of its aspects, a relay excitation winding is mounted about one leg of a substantially closed core which has an accommodating opening or window therethrough. At least part of the core is preferably thin in relation to its width, is of a single-lamination thickness, and is made of a low-reluctance and low coercive force material. At one position, the core is interrupted by a gap formed by two parallel overlapping ends of the core material, and a slender elongated cylindrical armature of permanent magnet material having diametric magnetization is disposed in the gap parallel with but spaced from both overlapping ends of the core. Low-friction pivots permit angular movement of the cylindrical magnet about its longitudinal axis, and the magnet poles are attracted to the unmagnetized core material such that the magnet tends to assume a particular angular orientation about that axis. Upon excitation of the core winding with a direct current of a given polarity, the overlapping core ends become magnetically polarized in a sense to cause repulsion effects upon the armature magnet poles, and the armature is then rotated in one direction. Mechanical stops limit angular excursions of the armature in a manner aiding the aforesaid operation, and electrical contacts "ice are opened and closed as the armature assumes one or the other of the permitted angular positions.

The subject matter regarded as our invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both as to organization and method of operation, and further, in relation to objects and advantages thereof, this invention may best be understood by reference to the following description taken in connection with the accompanying drawing, in which:

Figure 1 is a pictorial view of a polarized relay structure embodying teachings of this invention;

Figure 2 provides an exploded pictorial view of one portion of the relay illustrated in Figure 1;

Figure 3 shows in partial cross-section the details of an assembled armature structure such as that portrayed in Figures 1 and 2; and

Figure 4 is a simplified cross-sectional view of an armature and core assembly depicting suitable polarizations and angular orientations of elements.

The embodying apparatus portrayed in Figure 1 takes the form of a sensitive polarized relay having an excitation winding 1 encircling one portion or leg of a substantially closed core structure including two single-lamination core elements, 2 and 3. Both of these core elements comprise a low-reluctance and low-coercive-force material, that is, a material such as nicaloi which is a good conductor of magnetic flux but does not readily become permanently magnetized. Elements 2 and 3 are in an abutting laminated relationship only over the core portion where they are encircled by winding 1, and as can be perceived in the drawing, the core elements are also narrowed over this same portion such that a transverse cross-section of the abutting laminations is very nearly square. Elsewhere, each of elements 2 and 3 is of greater width, for the purpose of defining a special form of core gap, as is discussed later herein. The arrangement wherein the core elements of one thickness which are necessarily wide for one purpose are narrowed and laminated to provide a desired cross-section of material over the core portion surrounded by the excitation winding is of particular advantage in that a greater number of ampere-turns of winding can be realized with a given amount of wire. It will be apparent, for example, that another core, of half the thickness and some greater width yielding the same cross-sectional area of magnetic material, would have a longer periphery and would require more wire to complete each winding turn about it. Inasmuch as low-cost construction is aided through use of simple punched core elements each of a single thickness, rather than through use of core elements which are themselves of varying thickness, this arrangement for dividing, narrowing, and laminating part of the core is a distinct asset.

At another position along the core structure an air gap is formed between parallel overlapping ends or pole pieces 2 and 3 of the core elements 2 and 3, respectively. This gap accommodates an angularly movable magnetized armature 4, and the shape, dimensions, and spacing of the pole pieces 2 and 3 are critical in establishing proper intensities and distributions of magnetic flux through the gap. In most types of apparatus having movable armatures disposed between magnet poles, the cores are relatively thick and heavy such that wide pole piece surfaces may be had, such that the pole pieces may be machined accurately, and such that precise pole spacings will be preserved. It will be observed, however, that the pole pieces 2' and 3 are instead made as integral parts of thin punchings from sheet stock and that wide pole pieces are realized intermediate their overlapping surfaces. The pole pieces retain the perfectly flat and uniform surfaces of the sheet material from which they are punched, such that machining of these surfaces is not required. lrecise spacing of the oppositely disposed pole piece surfaces in a perfectly parallel relationship is required, and since the thin core elements 2 and 3 may tend to move under certain influences and thereby alter such spacing, the relative position of the pole piece surfaces is preserved by a carefully machined nonmagnetic spacer 5 which is fixed with and tightly sandwiched between pole pieces 2 and 3 by suitable fasteners such as set screw The desired air gap for armature is preserved by constructing spacer with two spaced 1 legs 7 and S, as is illustrated in the Figure 3 exploded view. Despite such movements as core elements 2 and may experience under influence of shock or vibration, the pole pieces :2 and 3 will thus unfailingly maintain their intended spaced parallel relationship.

Spa er element 5 also conveniently serves to mount the magnetized armature by way of a jewel pivot unit 9 threaded into an enlargement or boss it) on spacer 5. A glass jewel 11 or other sensitive low-friction hearing may be set -o unit 9, as is shown in Figure 3. Opposite the boss 1 there is mounted an insulating block 12 which 5 orts certain contact and stop elements and which also enables another jewel pivot unit, 13, to be threaded into A like jewel, 1 2 is fixed within this unit, and the bearing support provided for the armature -3 by the ts and is along the axis which is pa lei to and midway between the pole pieces 2' and 3'. 'th this construction, the armature is always maintained in alignment intermediate the electro- 11 :rgnet po es because the pole pieces, spacer, and pivot units are all rigidly fastened together.

Axi i alignment of the diametrically magnetized armature t along axis of angular movement 15-15 is not of a particularly critical nature, it merely being desirable that all such structures have the uniform-diameter portions of their armatures intermediate the edges of the pole pieces if their operating characteristics are to be alike. T he armature may be of a particularly slender elongated construction and is formed of a material which is readily permanently magnetized across a smaller dimension, cobalt-platinum alloy being such a material. By virtue of this construction the elongated armature itself is of extremely light weight with all of the mass concentrated near the axis of rotation, thereby reducing pivot frictions and inertias, rendering the apparatus insensitive to shock loadings and vibration eliects, and increasing the sensitivity and speed of armature response.

Angular orientations of the magnetized armature 4 about its pivot axis ll5-lt influence the operating characteristics. For example, the illustrated equipment opcrates on a magnetic toggle pri ci le, t polarize armature 5 to align its les with the low reluctance magn 2' and tron when windin it .e poles are repelled by magnetic r pulsion when by a signal of one polarity. Were the arm .ed to reach an equilibrium angular orienta 'on in relation to the pole pieces due to the magnetic attraction, it then could not be predicted in which angular direction the armature would turn when the pole pieces 2 and 3 became polarized in a sense to cause r pulsion of the armature poles. Accordingly, this instab ty is avoided through limitation of the permi sible angular excursions by the armature, one means for effecting this limitation comprising adjustable mechanical stop elements 17 and 13 in cooperation with stop surfaces of the contact arm 19. Referring to Figure the diametric magnetization of armature l is illustrated in the orientation realized when the relay coil is unencited and the armature is restrained by its stops from pulling into full alignment with the axis 2% normal to the surfaces of pole pieces 2, and 3'. The angular displacement from this fully aligned orientation is represented by angle 21. When winding l is excited with a D.-C. signal of suitable polarity, the pole pieces 2 and 3' have the polarities noted in Figure 4 and the armature 4 is repelled from these pole pieces and caused to move through a small angle 22 until other stops engage and prohibit further movement. Removal of excitation results in rapid return of the armature to the angular position shown, by reason of attraction of the magnet poles to the lowu luctance and low coercive force material of t s cor-e. Angle 21 may be small, although maximum repulsion torques about axis l5l5 are of course realized when the axis of diametric magnetization of the armature is not too close to axis 2%. Nor should the permitted angular movement of the armature enable its axis of magnetization to be displaced more than 90 from the axis 26, since the armature would then tend to remain in that position through attraction to the nearer pole pieces when the relay winding became unenergized. In one suitable construction, angle 21 has been approximately and angle 22 about 5.

The contact and stop arm 19 is rigidly fastened to armature l and is bent to the configuration best shown in Figure 2. A counterbalancing weight 23 is attached to one part of the arm, and a contact element 24 is formed at another position where it is disposed to engage and disengage the contact end 25 of adjustable member 17. Arm 19 is made of an electrically conductive material, for the switching purpose it serves, and a further elec trical contact is made with it through armature 4, torqueless conducting spiral Z6, and core to which the spiral is connected. The circuit opened and closed with the armature movements may be traced from lead 27, through member 17, contact end 25, contact 24, arm 19, armature 4, spiral 25, core elements 3 and 2, and through lead 28. Stop arm 18 engages the bent contact arm when relay winding l is unenergized, thereby limiting armature movement in one direction, and the engagement of contact element 24 with end 25 of member 17 suitably limits armature movement in the opposite angular direction. Both members it? and 18 are axially adjustable in their threaded relationship with insulating block 12, such that the limits of angular movement may be closely adjusted.

Although the present invention has been described with reference to a preferred form of electromechanical device, it should be apparent to those skilled in the art that our teachings may be practiced in connection with other apparatus arrangements without departure in spirit or scope from the invention as set forth in the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. Electrical apparatus comprising a substantially closed core having a pair of flat pole pieces each formed by a single flat length of low-coercive-force magnetic material having a width large in relation to its thickness, said pole pieces being disposed with the flat surfaces thereof in a spaced parallel relationship to define a narrow air gap said core, electrical winding means positioned to polarize said pole pieces oppositely when excited by a unidirectional current, an elongated armature of length greater than transverse dimension thereof and permanently magnetized transversely to the direction of elongation thereof, means mounting said armature intermediate said pole pieces for angular movement about an axis parallel with said pole pieces and parallel with said direction of elongation, stop means limiting angular movements of said armature to a range of less than degrees lying intermediate the angular positions at which said transverse magnetization is normal to and parallel with said pole pieces, and means responsive to angular movements of said armature characterizing the excitation of said Winding.

2. Sensitive electrical relay apparatus comprising a substantially closed core having a pair of pole pieces each formed by a single thin flat length of low-coerciveforce magnetic material having a width large in relation to its thicxness, said fiat pole pieces being disposed with the flat surfaces thereof in a spaced parallel relationship to define a narrow air gap in said core, electrical Winding means positioned on said core to polarize said pole pieces oppositely when excited by a unidirectional current, a slender right cylindrical armature of cobalt-platinum alloy permanently magnetized along one diameter, means mounting said armature intermediate said pole pieces for angular movement in said air gap about an axis parallel with said flat surfaces of said pole pieces, stop means limiting angular movements of said armature such that said armature assumes one predetermined angular orientation through magnetic attraction to said pole pieces when said winding is unexcited and moves in one angular direction through magnetic repulsion when said winding is excited with unidirectional current of one polarity, and electrical contact means opened and closed in response to angular movements of said armature.

3. Sensitive electrical relay apparatus comprising a substantially closed core having a pair of pole pieces each formed by a single thin flat length of low-coercive-force magnetic material having a width large in relation to its thickness, non-magnetic support means fastened to both of said pole pieces and rigidly maintaining flat surfaces of said pole pieces in a fixed spaced parallel relationship with a narrow air gap therebetween, electrical winding means positioned on said core to polarize said pole pieces oppositely when excited by a unidirectional current, an elongated armature of length greater than transverse dimensions thereof permanently magnetized transverse to the direction of elongation thereof, means mounting said armature on said non-magnetic support means intermediate said pole pieces for angular movement in said air gap about an axis parallel with the flat surfaces of said pole pieces and parallel with said direction of elongation, stop means limiting angular movements of said armature in relation to said pole pieces such that said armature assumes one predetermined angular orientation through magnetic attraction to said pole pieces when said winding is unexcited and moves in one angular direction through magnetic repulsion when said winding is excited with unidirectional current of one polarity, and electrical contact means supported by non-magnetic support means for electrical circuit connection and disconnection in response to angular movements of said armature.

4. Electrical apparatus comprising a pair of thin laminations made of low-coercive-force magnetic material, said laminations together forming a substantially closed core with said laminations in stacked abutting relationship over but one portion of said core and said laminations having flat ends disposed in a spaced parallel relationship over another portion of said core to define a gap in said core, said laminations having a thickness small in relation to their width at said ends and having the same thickness and lesser width over said one portion of said core, electrical winding means wound about said one portion of said core, a slender elongated right cylindrical armature permanently magnetized along one diameter and mounted for angular movement in said gap about an axis parallel with the flat surfaces of said spaced laminations, and means responsive to angular movements of said armature characterizing conditions of unidirectional current excitation of said winding.

5. Sensitive electrical relay apparatus comprising a pair of thin laminations made of low-coercive-force magnetic material, said laminations together forming a substantially closed core with said laminations in stacked abutting relationship over one portion of said core and said laminations having substantially fiat ends disposed in a spaced overlapping parallel relationship over another portion of said core to define a gap in said core, said laminations having a thickness small in relation to their width at said ends and having the same thickness and a lesser width over said one portion of said core, electrical winding means wound about said one portion of said core and polarizing said lamination ends oppositely when excited by a unidirectional current, non-magnetic spacer means fastened to said lamination ends and rigidly maintaining said lamination ends in a fixed spaced parallel relationship across said gap, an elongated right cylindrical armature permanently magnetized along one diameter, means mounting said armature intermediate said lamination ends for angular movement in said gap about an axis parallel with the flat surfaces of said lamination ends, stop means limiting angular movements of said armature such that said armature assumes one predetermined angular orientation through magnetic attraction to said lamination ends when said winding is unexcited and moves in one angular direction through magnetic repulsion when said winding is excited with unidirectional current of one polarity, and electrical contact means opened and closed in response to angular movements of said armature.

6. Sensitive electrical relay apparatus comprising a pair of thin laminations made of low-coercive-force magnetic material, said laminations together forming a substantially closed core with said laminations in stacked abutting relationship over one portion of said core and said laminations having substantially flat ends disposed in a spaced overlapping parallel relationship over another portion of said core to define a gap in said core, said laminations having a thickness small in relation to their width at said ends and having the same thickness and a lesser width over said one portion of said core, electrical winding means wound about said one portion of said core and polarizing said lamination ends oppositely when excited by a unidirectional current, non-magnetic support means fastened to both of said lamination ends and rigidly maintaining said lamination ends in said spaced parallel relationship across said gap, an elongated right cylindrical armature of cobalt-platinum alloy permanently magnetized along one diameter, means mounting said armature in said non-magnetic support means for angular movement in said gap about an axis parallel with the flat surfaces of said lamination ends, cooperating stop means on said armature and said support means limiting angular movements of said armature in relation to said lamination ends such that said armature assumes one predetermined angular orientation through magnetic attraction to said lamination ends when said winding is unexcited and moves in one angular direction through magnetic repulsion when said winding is excited with unidirectional current of one polarity, and electrical contact means supported by said non-magnetic support means for electrical circuit connection and disconnection in response to angular movements of said armature.

References Cited in the file of this patent UNITED STATES PATENTS 650,531 Fessenden May 29, 1900 863,692 Bliss Aug. 20, 1907 1,982,811 Hill Dec. 4, 1934 2,102,409 Faus Dec. 14, 1937 2,175,046 Warner Oct. 3, 1939 2,635,155 Barr Apr. 14, 1953 FOREIGN PATENTS 69,598 Austria Aug. 10, 1915 

